List of fallacies


In reasoning to argue a claim, a fallacy is reasoning that is evaluated as logically incorrect and that undermines the logical validity of the argument and permits its recognition as unsound. Regardless of their soundness, all registers and manners of speech can demonstrate fallacies.
Because of their variety of structure and application, fallacies are challenging to classify. Fallacies can be classified strictly by either their structure or content. The classification of informal fallacies may be subdivided into categories such as linguistic, relevance through omission, relevance through intrusion, and relevance through presumption. Or, fallacies may be classified by the process by which they occur, such as material fallacies, verbal fallacies, and again formal fallacies. Material fallacies may be placed into the broader category of informal fallacies, while formal fallacies may be placed into the more precise category of logical fallacies. Yet, verbal fallacies may be placed into either informal or deductive classifications; compare equivocation which is a word or phrase based ambiguity to the fallacy of composition which is premise and inference based ambiguity.
The conscious or habitual use of fallacies as rhetorical devices is prevalent in the desire to persuade when the focus is more on communication and eliciting common agreement rather than on correctness of the reasoning. The effective use of a fallacy may be considered clever, but the reasoning should be recognized as unsound and the conclusion regarded as unproven.

Formal fallacies

A formal fallacy is an error in logic that can be seen in the argument's form. All formal fallacies are specific types of Non sequitur.
A propositional fallacy is an error in logic that concerns compound propositions. For a compound proposition to be true, the truth values of its constituent parts must satisfy the relevant logical connectives that occur in it. The following fallacies involve inferences whose correctness is not guaranteed by the behavior of those logical connectives and are not logically guaranteed to yield true conclusions.

Types of propositional fallacies:
A quantification fallacy is an error in logic where the quantifiers of the premises are in contradiction to the quantifier of the conclusion.

Types of quantification fallacies:
– logical fallacies that occur in syllogisms.
Informal fallacies – arguments that are logically unsound for lack of well-grounded premises.
– reach a conclusion from weak premises. Unlike fallacies of relevance, in fallacies of defective induction, the premises are related to the conclusions yet only weakly support the conclusions. A faulty generalization is thus produced.
is a general type of error with many variants. Its primary basis is the confusion of association with causation, either by inappropriately deducing causation or a broader failure to properly investigate the cause of an observed effect.
A red herring fallacy, one of the main subtypes of fallacies of relevance, is an error in logic where a proposition is, or is intended to be, misleading in order to make irrelevant or false inferences. In the general case any logical inference based on fake arguments, intended to replace the lack of real arguments or to replace implicitly the subject of the discussion.
Red herring – introducing a second argument in response to the first argument that is irrelevant and draws attention away from the original topic. See also irrelevant conclusion.